JP2008262863A - Mems switch and integrated circuit equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an MEMS switch with downsizing aimed at and an integrated circuit equipped with the same by dint of magnetic drive capable of putting on/off a large-capacity current. <P>SOLUTION: A support part 2 is erected on a silicon substrate 1 by an MEMS (Micro Electro-mechanical System) technology, and at a tip end of the support part 2, a plate-like magnetic body 3 is provided put in parallel with the surface of the silicon substrate 1. A first contact point 4 is fitted at an inside of one end of the magnetic body 3, and in opposition to it, a second contact point 6 is fitted on the silicon substrate 1. When the magnetic body 3 is imparted with magnetism from the side of the silicon substrate 1, the latter is suctioned and bent, the first contact point 4 comes in contact with the second contact point 6 to have the switch put on, and when the magnetism is gone, the magnetic body 3 returns to a standby position. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a MEMS switch that opens and closes depending on the presence or absence of magnetism, and an integrated circuit including the same.

  Most of the switches that are turned on / off by mechanically contacting a pair of contacts are manually operated, but there are also switches that are operated by an electric signal.

  For example, there is what is shown in Patent Document 1, and two fixed optical fibers are arranged in one of grooves formed in a straight line on a substrate by a MEMS (Micro Electro Mechanical System), and the tip is fixed. A movable optical fiber is disposed in the groove so as to face and oscillate the optical fiber, a leaf spring is interposed at the free end, and the leaf spring is driven by an electromagnet to displace the movable optical fiber. An optical switch that performs switching is disclosed.

Also known is a semiconductor switch that generates a switch signal by combining a magnetic sensor, for example, an MR element and a permanent magnet, and operates the semiconductor switching element by this switch signal.
JP 2004-94088 A

  However, according to the conventional optical switch, in the case of the configuration of Patent Document 1, the configuration becomes complicated and the size increases when it is applied to the on / off of the current. In addition, when an MR (magnetoresistive effect) element is used for the switch, a combination with a semiconductor switching element is essential, and the switch cannot be configured alone.

  Accordingly, it is an object of the present invention to provide a magnetically driven MEMS switch that can be miniaturized and that can turn on / off a large-capacity current, and an integrated circuit including the same.

[1] According to the first aspect of the present invention, a silicon substrate having a projecting support provided by MEMS (Micro Electro Mechanical System), and provided on the support in parallel to the surface of the silicon substrate. A plate-shaped magnetic body, a first contact provided inside the tip of the magnetic body, a second contact provided on the surface of the silicon substrate opposite to the first contact, A MEMS switch characterized by comprising:

[2] According to the second aspect of the present invention, the MEMS switch according to [1], a magnetic sensor provided alongside the MEMS switch, and a package in which the MEMS switch and the magnetic sensor are integrally sealed. And an integrated circuit characterized by comprising:

[3] The magnetic sensor may be a giant magnetoresistive element, magnetoresistive element, or Hall element.

  According to the embodiment of the present invention, it is possible to obtain a MEMS switch which can be miniaturized and which can turn on / off a large-capacity current and an integrated circuit including the MEMS switch.

[First Embodiment]
FIG. 1 is a front sectional view showing a MEMS switch according to a first embodiment of the present invention.

(Configuration of MEMS switch)
The MEMS switch 100 is provided inside the silicon substrate 1, the support portion 2 provided on the silicon substrate 1 by MEMS technology, the magnetic body 3 attached to the upper end of the support portion 2, and the tip of the magnetic body 3. The first contact 4, the wiring pattern 5 having one end connected to the one end and the other end wired on the silicon substrate 1, and the second provided on the silicon substrate 1 facing the contact 4. The contact 6, the wiring patterns 7 A and 7 B provided on the silicon substrate 1, the wire 14 connecting the wiring pattern 5 and the wiring pattern 7 B, and the movable portion and the first and second contacts 4 and 6. The package 20 is configured to be sealed with a space.

  The support portion 2 is configured by, for example, etching the silicon substrate 1, or is configured by hot embossing or the like that forms unevenness by heating a material using a mold.

  The magnetic body 3 is configured to have a predetermined thickness by, for example, depositing or vapor-depositing a magnetic metal such as Fe or Fe alloy, and is fixed to the upper end of the support portion 2 by, for example, room temperature bonding or adhesion.

  The first and second contacts 4 and 6 are provided, for example, by vapor deposition so as to have a size and thickness that do not melt even when several amperes flow.

  The wiring patterns 5, 7 </ b> A, and 7 </ b> B are provided by, for example, vapor deposition, etching, etc.

  The wiring patterns 7A and 7B serve as switch on / off output terminals. Therefore, lead wires, pins and the like for connecting to the outside are connected to the wiring patterns 7A and 7B.

  The wire 14 is a bonding wire such as a gold wire.

  The package 20 is a resin material having heat resistance and moisture resistance, and is provided by resin molding.

  Next, the operation of the MEMS switch 100 will be described.

(Operation of MEMS switch)
FIG. 2 is a perspective view showing a mounting example of the MEMS switch 100. As shown in FIGS. 1 and 2, the MEMS switch 100 is disposed along the moving path of the magnet 10 attached to the end of the plunger 11.

  As shown in FIG. 2, the plunger 11 can reciprocate in the directions of arrows A and B in FIG. 1 while being guided by a cylindrical holder 12 and a guide 13.

  The holder 12 is mounted with the MEMS switch 100 shown in FIG. 1 on the outer peripheral surface, and the wiring patterns 7A and 7B of the MEMS switch 100 have a pair of leads whose other ends are connected to a brake lamp circuit or the like (not shown). One end of the line 8 is connected.

  One end of the plunger 11 is coupled to a brake link of an automobile, for example. When the driver steps on a brake pedal (not shown), the plunger 11 moves in the direction A shown in FIGS. Moves in direction B when released.

  When the magnet 10 at the other end of the plunger 11 moves from the B position to the A position as the plunger 11 moves, the magnetic attractive force on the magnetic body 3 gradually increases as the magnet 10 approaches the magnetic body 3. The magnetic body 3 bends toward the silicon substrate 1 side.

  When the magnetic attraction force with respect to the magnetic body 3 exceeds a certain level, the first contact 4 and the second contact 6 come into contact with each other and the switch is turned on. As a result, the current flows through the route of the wiring pattern 7B, the wiring pattern 5, the first contact 4, the second contact 6, and the wiring pattern 7A.

  Next, when the magnet 10 moves from the A position to the B position as the plunger 11 moves, the magnetic attractive force with respect to the magnetic body 3 gradually decreases, and the magnetic body 3 gradually returns to the horizontal state. The contact between the first contact 4 and the second contact 6 is released and the switch is turned off.

(Method for manufacturing MEMS switch)
FIG. 3 is a process diagram showing a manufacturing method of the MEMS switch. Below, the manufacturing method of a MEMS switch is demonstrated with reference to FIG. Although FIG. 1 shows a configuration for one switch, in practice, a large number of switches are simultaneously manufactured on a silicon wafer or the like, and finally diced for individualization.

  First, as shown in FIG. 3B, portions other than the support portion 2 are removed from the silicon substrate 1 shown in FIG. 3A by DRIE (Deep Reactive Ion Etching).

  Next, as shown in FIG. 3C, a resist 9 is applied to portions other than the portions where the wiring patterns 7A and 7B on the surface of the silicon substrate 1 are provided. Next, wiring patterns 7A and 7B made of an Au film are formed on the portion where the resist 9 is not applied by, for example, electron beam evaporation.

  Next, as shown in FIG. 3D, after a resist is provided in a portion other than the second contact 6, a second contact 6 made of an Au film is formed on a predetermined portion of the wiring pattern 7A by electron beam evaporation. To do. The resist is removed after this step.

  Next, as shown in FIG. 3E, in another process, the magnetic body 3 having the first contact 4 and the wiring pattern 5 is manufactured. The end portion of the magnetic body 3 is joined to the upper end surface of the support portion 2, and the wiring pattern 5 and the wiring pattern 7B are wire-bonded by the wire 14, thereby completing the MEMS switch 100.

  Finally, an internal space in which the first contact 4 can freely swing and the first contact 4 and the second contact 6 can be mechanically turned on / off is secured, so that the silicon substrate 1 The periphery is sealed with the package 20.

(Effects of the first embodiment)
According to the first embodiment, the following effects are obtained.
(1) By using the MEMS technology, it is possible to pass a large current by switching on while reducing the size.
(2) Since the silicon substrate 1 and the support part 2 of the main part are manufactured using the MEMS technology, mass productivity and reliability can be improved.

[Second Embodiment]
FIG. 4 is a front sectional view showing an integrated circuit according to the second embodiment of the present invention.

(Configuration of integrated circuit)
In this embodiment, the integrated circuit 200 is configured by mounting the magnetic sensor 21 together with the MEMS switch 100 on the common silicon substrate 1 in the first embodiment and sealing them with a package 20 made of resin mold. Is.

  Note that since the MEMS switch 100 has a small size, it does not actually have the same size as the magnetic sensor 21, but in FIG. 4, the configuration is enlarged to facilitate the understanding of the configuration. .

  The magnetic sensor 21 is configured using, for example, a GMR (giant magnetoresistive effect) element, an MR element (magnetoresistive effect) or a Hall element as a magnetic detection element. Among these, since the GMR element has the highest detection sensitivity, a highly sensitive magnetic sensor 21 can be configured.

  The magnetic sensor 21 is mounted on a predetermined position by solder or the like after the MEMS switch 100 is provided on the silicon substrate 1.

  The silicon substrate 1 has an area where the MEMS switch 100 and the magnetic sensor 21 can be mounted, and includes a wiring pattern (not shown) connected to the wiring patterns and terminals of the MEMS switch 100 and the magnetic sensor 21.

  Further, the silicon substrate 1 has a plurality of outer leads 22 connected to the wiring patterns 5, 7 </ b> A, 7 </ b> B of the silicon substrate 1 and the terminals of the magnetic sensor 21. The outer lead 22 is connected to the wiring pattern 7 through the through hole 23. The outer leads connected to the wiring pattern 7B and the terminals of the magnetic sensor 21 are not shown.

(Operation of integrated circuit)
Next, the operation of the integrated circuit 200 will be described. The integrated circuit 200 is attached to the holder 12 as shown in FIG.

  In FIG. 1, when the magnet 10 moves from the B position to the A position as the plunger 11 moves, the magnetic force of the magnet 10 on the magnetic body 3 and the magnetic sensor 21 gradually increases, and the magnetic body 3 is on the silicon substrate 1 side. The magnetic sensor 21 outputs a detection signal corresponding to the magnetic force.

  When the magnetic attractive force on the magnetic body 3 exceeds a certain level, the first contact 4 and the second contact 6 come into contact with each other and the switch is turned on. As a result, the current flows through the route of the wiring pattern 7B, the wiring pattern 5, the first contact 4, the second contact 6, and the wiring pattern 7A.

  In addition, a signal processing circuit (not shown) connected to the magnetic sensor 21 generates a driving signal when a predetermined threshold is exceeded with respect to the detection output of the magnetic sensor 21, and operates a switching element such as a semiconductor switching element or a relay. Let

  Next, when the magnet 10 moves from the A position to the B position as the plunger 11 moves, the magnetic attractive force with respect to the magnetic body 3 gradually decreases, and the magnetic body 3 gradually returns to the horizontal state. The contact between the first contact 4 and the second contact 6 is released and the switch is turned off.

  When the magnet 10 moves from the B position to the A position, the magnetic force gradually decreases in the magnetic sensor 21, and the detection output gradually decreases. When the detection output is less than or equal to the threshold value, the output signal is lost from the signal processing circuit, and the switch element is turned off.

(Effect of the second embodiment)
According to the second embodiment, the following effects are obtained.
(1) Since the magnetic sensor 21 is operated together with the MEMS switch 100 to drive the switch element, the load can be reliably turned on / off, and the reliability and safety can be improved.
(2) In the MEMS switch 100, the same effect as the first embodiment can be obtained.

[Other embodiments]
The present invention is not limited to the above embodiments, and various modifications can be made without departing from or changing the technical idea of the present invention.

It is front sectional drawing which shows the MEMS switch which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the example of mounting | wearing of a MEMS switch. It is process drawing which shows the manufacturing method of a MEMS switch. It is front sectional drawing which shows the integrated circuit which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Support part 3 Magnetic body 4 1st contact 5 Wiring pattern 6 2nd contact 7A, 7B Wiring pattern 8 Lead wire 9 Resist 10 Magnet 11 Plunger 12 Holder 13 Guide 14 Wire 20 Package 21 Magnetic sensor 22 Outer lead 23 Through-hole 100 MEMS switch 200 Integrated circuit

Claims (3)

A silicon substrate having a protruding support provided by MEMS (Micro Electro Mechanical System);
A plate-like magnetic body provided on the support portion in parallel with the surface of the silicon substrate;
A first contact provided inside the tip of the magnetic body;
A second contact provided on the surface of the silicon substrate opposite to the first contact;
A MEMS switch comprising: A MEMS switch according to claim 1;
A magnetic sensor attached to the MEMS switch;
A package integrally sealing the MEMS switch and the magnetic sensor;
An integrated circuit comprising:   The integrated circuit according to claim 2, wherein the magnetic sensor is a giant magnetoresistive element, a magnetoresistive element, or a Hall element.

Images